Practical considerations also limit the choice of lenses you can use, Steve.
If you want to get the thing in the frame as large as possible, you would need approximately a 2x magnification on 6x6. That means adding 2x the focal length of the lens in extra extension. Which is a lot.
And the obvious Hasselblad lens candidates for close-up photography are the Planars, the 120 and 135 mm Makro-Planars and the 'humble' 80 mm Planar.
The 135 mm is a 'bellows-head' lens, and needs the bellows extension unit even for infinity focus. With the bellows fully extended, it reaches 1:1, so it would need another 135 mm of extension to get to 2:1. Another three extension tubes (at least)? Not something i would try.
If you do, the front lens to subject distance will be 138 mm.
The 120 mm, being in a focussing mount that already offers extension, is a better choice. Fully extended, it will need an additional 216 mm of extension to get to 2:1. The automatic bellows unit will provide 202 mm, so a single additional short tube is required as well.
The front lens to subject distance will also be 138 mm.
The 80 mm Planar, though not a macro lens, produces excellent results in this range as well. It will need an additional 153 mm, so the bellows unit alone will do.
Front lens to subject distance will be 82 mm.
Anything shorter out of the Hasselblad lens line, and results will not be good enough. With shorter lenses all being retrofocus types, front lens to subject distances will rapidly decrease too (only 37 mm with the 60 mm lens, 23 with the 50 mm). The latter bit would also exclude special macro lenses like the Zeiss Luminars: most of them are too short perhaps to provide the working distance needed.
Anything longer and not only will the results be less than satisfactory, but the set-up will become unmanageable too.
The other Planars (100 mm and 110 mm), though not too short or too long, i wouldn't consider. Not quite up to par in this range.
But if you'd like anyway: the 100 mm would need an additional 187 mm (which means the bellows unit). The front lens to subject distance will then be 109 mm.
The 110 mm (i really wouldn't!) will need 201 mm of extra extension (bellows). Front lens to subject distance would be 106 mm.
So, i think, the only choice there is, is that between the 80 mm and the 120 mm lenses.
Neither is made for this scale (no Hasselblad lens is). But neither is outside its comfort zone doing this either. They will produce excellent results!
Which Hassie lenses do you have? On my Contax 645, I use the 210 mm Sonnar with the 80 mm Planar reverse mounted on the front of it. The filters are the same size, so I just superglued two Lee filter holding rings together face-to-face to hold the Planar. It works well, but the setup is prone to vibration - solid tripod, mirror lock, no wind, etc, are all essential. You get a 210/80 = 2.6 magnification ratio though.
The other setup I use with the Contax is 1.4 TC + 52 mm extension tube + 120 mm Macro Planar fully extended. That give just over 2 magnification.
I haven't tried reverse mounting the 80 mm Planar on front of the second setup ... now there's a thought.
Not that you need another camera, but this is where the Rolleiflex SL66 shines.
It has bellows that give you 1:2, and you can reverse mount the lens without any adapters.
Works fine, especially if you want to stick with Zeiss lenses.